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|
//! freeq's AV media plane, for callers that are not Rust.
//!
//! sleek reaches its calls by calling Rust from Rust. A client written in
//! anything else cannot, and this is not a plane to write twice: MoQ over
//! QUIC, Opus, H.264, camera capture and the SFU's own dial rules come to some
//! three thousand lines that would say exactly the same thing again in another
//! language, and be wrong in different places.
//!
//! So it was lifted out of sleek to here, and what crosses the boundary is
//! only what jolt can hold: integers, doubles, borrowed UTF-8 strings, and one
//! borrowed pixel pointer.
//!
//! # What is not here
//!
//! **Signaling.** A freeq call is opened, joined and left over IRC TAGMSGs —
//! `+freeq.at/av-start` and its siblings — and the server answers with
//! `+freeq.at/av-state`. Any client that can speak IRC already has everything
//! it needs for that, in whatever language it speaks IRC in; crossing an FFI
//! boundary to send a TAGMSG would be worse than not. This library begins once
//! the session id and the SFU token are known, and ends when the call does.
//!
//! # The shape of it
//!
//! **Nothing calls back.** Status arrives through [`joltmoq_poll_status`],
//! video through [`joltmoq_frame_poll`], both drained from whatever thread the
//! caller paints on — see [`jolt_abi`] for why.
//!
//! **One call at a time.** There is one microphone, so there is one session,
//! held in a global. A handle would imply a second call could run beside the
//! first, which is not something the hardware or the person would enjoy.
//!
//! **Frames are borrowed, not copied.** [`joltmoq_frame_rgba`] hands out a
//! pointer into the decoder's own buffer, good until the next poll. A frame is
//! a megabyte or two; copying it out so the caller can hand it straight to a
//! texture upload would be two copies a frame to no end.
pub mod av;
pub mod av_media;
// Pure arithmetic on planes, so it builds and is tested everywhere even though
// only the Android camera path calls it — a rotate is easier to get wrong than
// to test, and a desktop `cargo test` is where that gets caught.
#[cfg_attr(not(target_os = "android"), allow(dead_code))]
mod nv12_orient;
// V4L2 is Linux's camera interface and the phone does not offer it; there the
// camera is Java, reached through the two modules below.
#[cfg(not(target_os = "android"))]
mod v4l2cam;
#[cfg(target_os = "android")]
mod android_camera;
#[cfg(target_os = "android")]
mod android_jni;
use std::collections::HashMap;
use std::ffi::{c_char, c_int};
use std::sync::{Mutex, OnceLock};
use jolt_abi::{borrowed, empty_str, guard, preference, Scratch};
use av::{RgbaVideoFrame, VideoFrameStore};
use av_media::{AvMediaConfig, AvMediaSession, AvMediaUpdate};
/// One scratch per family of string-returning calls, so that asking for the
/// video keys does not invalidate a device list the caller is still reading.
static STATUS_TEXT: Scratch = Scratch::new();
static FRAME_KEY: Scratch = Scratch::new();
static VIDEO_KEYS: Scratch = Scratch::new();
static DEVICES: Scratch = Scratch::new();
static DIAL: Scratch = Scratch::new();
// ── The one session ─────────────────────────────────────────────────────────
/// Everything a live call holds on this side.
#[derive(Default)]
struct Slot {
session: Option<AvMediaSession>,
/// Which session the statuses below belong to.
///
/// Tearing a call down is spawned rather than waited for, so the task of a
/// call that has ended outlives the call — and finishes, and reports that
/// it ended, possibly after the *next* call has started. Without a way to
/// tell whose news this is, the old session's dying breath tears down the
/// new one, which is exactly what rejoining a call did.
///
/// Bumped on every start and every stop, so anything a departed session
/// still has to say is discarded rather than acted on.
generation: u64,
/// Status updates from the media task, waiting to be polled, each with the
/// generation it was produced under.
status: Vec<(u64, Status)>,
/// The status most recently handed out, whose fields the accessors read.
current: Option<Status>,
/// The live session's frame store, and the generation last handed out per
/// feed — which is how a poll knows what is new.
video: Option<VideoFrameStore>,
seen: HashMap<String, u64>,
/// The frame most recently handed out. Held so that the pixel pointer the
/// caller was given stays alive until the next poll replaces it.
frame: Option<(String, RgbaVideoFrame)>,
}
#[derive(Clone)]
enum Status {
Live { has_camera: bool, has_mic: bool },
Ended,
Failed(String),
}
fn session_slot() -> &'static Mutex<Slot> {
static SLOT: OnceLock<Mutex<Slot>> = OnceLock::new();
SLOT.get_or_init(|| Mutex::new(Slot::default()))
}
/// A tokio runtime of our own: the caller has no reactor to lend us.
///
/// Deliberately *not* in the slot. Tearing a call down needs the runtime and
/// must not be holding the slot lock while it does — see [`joltmoq_stop`].
/// Made once and kept, since building one per call would tear worker threads
/// down and up again on every join.
fn runtime() -> Option<&'static tokio::runtime::Runtime> {
static RUNTIME: OnceLock<Option<tokio::runtime::Runtime>> = OnceLock::new();
RUNTIME
.get_or_init(|| {
tokio::runtime::Builder::new_multi_thread()
.enable_all()
.thread_name("joltmoq")
.build()
.map_err(|e| log::error!("joltmoq: no runtime: {e}"))
.ok()
})
.as_ref()
}
/// Run `f` against the one session, catching panics on the way out.
///
/// `fallback` answers both a panic and a poisoned lock, and is deliberately
/// taken by value rather than requiring `Copy`: the answer is sometimes a
/// `String`. The `Option` is how one value serves both arms without being
/// moved twice.
fn with_slot<R>(fallback: R, f: impl FnOnce(&mut Slot) -> R) -> R {
guard(None, || match session_slot().lock() {
Ok(mut slot) => Some(f(&mut slot)),
Err(_) => None,
})
.unwrap_or(fallback)
}
// ── Lifecycle ───────────────────────────────────────────────────────────────
/// Hand over the phone's `JavaVM` and Activity. Android only, and required
/// there before a call with a camera in it can start.
///
/// The camera on Android is Java, and this library cannot reach the handles a
/// JNI call needs: `android-activity`'s glue receives them, and the glue is in
/// `libvidya.so`. So the glue in `android/jolt_main.c` — which links both
/// objects — reads them out of libvidya's C ABI and passes them here, once,
/// before Jolt starts. See `android_jni` for why `ndk_context` cannot do this.
///
/// Everything else works without it. Only the camera calls fail, and they say
/// which call was missed rather than crashing.
///
/// # Safety
/// `vm` is the process's `JavaVM` and `activity` a global reference to the
/// running Activity, both live for the rest of the process — which is what
/// `vidya_android_vm` and `vidya_android_activity` return.
#[cfg(target_os = "android")]
#[no_mangle]
pub unsafe extern "C" fn joltmoq_android_init(
vm: *mut std::ffi::c_void,
activity: *mut std::ffi::c_void,
) {
guard((), || {
if vm.is_null() || activity.is_null() {
log::error!("joltmoq_android_init: null JavaVM or Activity; camera will not open");
return;
}
// SAFETY: the caller's contract, restated on this function.
unsafe { android_jni::set(vm.cast(), activity.cast()) };
log::info!("joltmoq: Android JNI handles received");
})
}
/// Turn on logging to stderr, honouring `RUST_LOG`. Safe to call twice.
///
/// Worth calling first while a call refuses to connect: the media plane says a
/// great deal about why, and says none of it otherwise.
#[no_mangle]
pub extern "C" fn joltmoq_init_logging() {
guard((), || {
let _ = env_logger::try_init();
})
}
/// Join the call at `sfu_url` as `nick`, answering 1 when the media task
/// started.
///
/// `sfu_url` is what [`joltmoq_sfu_url`] built, `session_id` is the id the
/// server broadcast in `+freeq.at/av-id`, and `instance` is the per-device id
/// the caller put in its own `av-join` — two devices signed in as the same
/// person need different ones or their broadcast paths collide and each
/// unpublishes the other.
///
/// The rest are pre-call preferences: `muted`, `speaker_muted` and `camera` as
/// 0 or 1, then three device preferences, each an empty string for "whatever
/// the system uses".
///
/// This returns as soon as the task is spawned. Connecting takes a moment, and
/// it is [`joltmoq_poll_status`] that says whether it worked. Starting a second
/// call while one is live is refused; stop the first.
///
/// # Safety
/// Every pointer is null or a NUL-terminated UTF-8 string.
#[no_mangle]
#[allow(clippy::too_many_arguments)]
pub unsafe extern "C" fn joltmoq_start(
sfu_url: *const c_char,
session_id: *const c_char,
nick: *const c_char,
instance: *const c_char,
muted: c_int,
speaker_muted: c_int,
camera: c_int,
camera_id: *const c_char,
mic_id: *const c_char,
speaker_id: *const c_char,
) -> c_int {
let sfu_url = borrowed(sfu_url);
let session_id = borrowed(session_id);
let nick = borrowed(nick);
let instance = borrowed(instance);
let camera_id = preference(borrowed(camera_id));
let mic_id = preference(borrowed(mic_id));
let speaker_id = preference(borrowed(speaker_id));
let Some(runtime) = runtime() else {
return 0;
};
with_slot(0, |slot| {
if slot.session.is_some() {
log::warn!("joltmoq: a call is already live; stop it first");
return 0;
}
let Ok(url) = url::Url::parse(&sfu_url) else {
log::warn!("joltmoq: not a URL: {sfu_url}");
return 0;
};
let config = AvMediaConfig {
sfu_url: url,
session_id,
nick,
instance,
muted: muted != 0,
speaker_muted: speaker_muted != 0,
camera_enabled: camera != 0,
camera_id,
mic_id,
speaker_id,
};
// `AvMediaSession::start` spawns onto the ambient runtime, so it has to
// be entered. The status closure it takes runs on a worker thread,
// which is why all it does is push onto a queue the caller drains.
slot.generation = slot.generation.wrapping_add(1);
let generation = slot.generation;
let _entered = runtime.enter();
let session = AvMediaSession::start(config, move |update| {
let status = match update {
AvMediaUpdate::Live {
has_camera,
has_mic,
..
} => Status::Live {
has_camera,
has_mic,
},
AvMediaUpdate::Ended => Status::Ended,
AvMediaUpdate::Failed(e) => Status::Failed(e),
};
if let Ok(mut slot) = session_slot().lock() {
// Dropped on the floor if this session is no longer the
// current one — see `Slot::generation`.
if slot.generation == generation {
slot.status.push((generation, status));
}
}
});
slot.video = Some(session.video.clone());
slot.session = Some(session);
slot.seen.clear();
slot.frame = None;
1
})
}
/// Leave the call: unpublish, drop the devices, forget the frames.
///
/// Waits briefly for the media task to tear MoQ down rather than aborting it
/// outright. An abandoned broadcast lingers on the SFU and peers subscribe to
/// it, so they see someone present and hear silence.
#[no_mangle]
pub extern "C" fn joltmoq_stop() {
// Take the session out from under the lock and let the lock go *before*
// anything waits on it.
//
// Waiting while holding it deadlocks, and did: the status callback locks
// this same slot from a tokio worker, so a task that still had an update
// to deliver could not finish, while the thread that would have released
// the lock was waiting for exactly that task to finish. The caller's UI
// thread is the one that hangs, which is every thread it has.
let session = with_slot(None, |slot| {
slot.video = None;
slot.seen.clear();
slot.frame = None;
// Nothing this session says from here on is about the call the caller
// is in, because it is not in one — and may be in a different one by
// the time the task gets round to saying it.
slot.generation = slot.generation.wrapping_add(1);
slot.status.clear();
slot.current = None;
slot.session.take()
});
let Some(mut session) = session else {
return;
};
// Not waited for either. Tearing MoQ down is a network round trip, and the
// press that asked for it was on the thread that paints — half a second of
// frozen window is not the answer to "leave". The teardown still runs, and
// still unpublishes properly: an abandoned broadcast lingers on the SFU and
// peers subscribe to it, seeing someone present who is silent.
match runtime() {
Some(runtime) => {
runtime.spawn(async move {
session
.stop_and_wait(std::time::Duration::from_secs(2))
.await;
});
}
// No runtime means no call ever started; nothing to unwind gracefully.
None => session.stop(),
}
}
/// 1 while a call is live on this side.
#[no_mangle]
pub extern "C" fn joltmoq_is_live() -> c_int {
with_slot(0, |slot| slot.session.is_some() as c_int)
}
// ── Controls ────────────────────────────────────────────────────────────────
/// Mute or unmute the microphone. Peers stop hearing you; you still hear them.
#[no_mangle]
pub extern "C" fn joltmoq_set_muted(muted: c_int) {
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_muted(muted != 0);
}
})
}
/// Mute or unmute remote audio — deafen. Deliberately not the same control as
/// [`joltmoq_set_muted`]: peers still hear you if the microphone is open.
#[no_mangle]
pub extern "C" fn joltmoq_set_speaker_muted(muted: c_int) {
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_speaker_muted(muted != 0);
}
})
}
/// Start or stop publishing camera. The device is only held while publishing,
/// so turning it off gives the hardware back to the rest of the machine.
#[no_mangle]
pub extern "C" fn joltmoq_set_camera(enabled: c_int) {
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_camera_enabled(enabled != 0);
}
})
}
/// Re-open the camera by id; an empty string means the first available.
///
/// # Safety
/// `id` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn joltmoq_set_camera_device(id: *const c_char) {
let id = preference(borrowed(id));
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_camera_device(id);
}
})
}
/// Switch microphone by name; an empty string means the system default.
///
/// # Safety
/// `id` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn joltmoq_set_mic_device(id: *const c_char) {
let id = preference(borrowed(id));
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_mic_device(id);
}
})
}
/// Switch speaker by name; an empty string means the system default.
///
/// # Safety
/// `id` is null or a NUL-terminated UTF-8 string.
#[no_mangle]
pub unsafe extern "C" fn joltmoq_set_speaker_device(id: *const c_char) {
let id = preference(borrowed(id));
with_slot((), |slot| {
if let Some(s) = &slot.session {
s.set_speaker_device(id);
}
})
}
/// The live microphone envelope, 0.0 to 1.0 — what a level meter draws. 0 when
/// no call is up.
#[no_mangle]
pub extern "C" fn joltmoq_mic_level() -> f64 {
with_slot(0.0, |slot| {
slot.session
.as_ref()
.map_or(0.0, |s| s.mic_level.get() as f64)
})
}
// ── Status ──────────────────────────────────────────────────────────────────
/// Nothing waiting.
pub const JOLTMOQ_STATUS_NONE: c_int = 0;
/// Connected and publishing.
pub const JOLTMOQ_STATUS_LIVE: c_int = 1;
/// The session ended cleanly.
pub const JOLTMOQ_STATUS_ENDED: c_int = 2;
/// Connect or runtime failure; [`joltmoq_status_text`] says what.
pub const JOLTMOQ_STATUS_FAILED: c_int = 3;
/// Dequeue one status update, or 0 when there is none.
///
/// The media task produces these on its own threads; this hands them to the
/// caller's. Drain it until it answers 0 wherever the caller polls — beside a
/// repaint is the natural place. Missing an update means a call that is up
/// still looks like it is connecting.
#[no_mangle]
pub extern "C" fn joltmoq_poll_status() -> c_int {
with_slot(JOLTMOQ_STATUS_NONE, |slot| {
// Drop anything a replaced session left behind, rather than stopping
// at it: answering NONE on a stale entry would strand every fresh one
// queued behind it.
let current = slot.generation;
slot.status.retain(|(generation, _)| *generation == current);
if slot.status.is_empty() {
slot.current = None;
return JOLTMOQ_STATUS_NONE;
}
let (_, status) = slot.status.remove(0);
let code = match &status {
Status::Live { .. } => JOLTMOQ_STATUS_LIVE,
Status::Ended => JOLTMOQ_STATUS_ENDED,
Status::Failed(_) => JOLTMOQ_STATUS_FAILED,
};
slot.current = Some(status);
code
})
}
/// Why the last polled status failed; the empty string for any other status.
///
/// # Safety
/// The returned pointer is valid until the next call to this function.
#[no_mangle]
pub extern "C" fn joltmoq_status_text() -> *const c_char {
let text = with_slot(String::new(), |slot| match &slot.current {
Some(Status::Failed(e)) => e.clone(),
_ => String::new(),
});
if text.is_empty() {
return empty_str();
}
STATUS_TEXT.lend(text)
}
/// 1 when the last polled `live` status found a capture device for this call.
///
/// A call can be live with no camera at all, so a caller shows a camera control
/// only when there is something for it to turn on.
#[no_mangle]
pub extern "C" fn joltmoq_status_has_camera() -> c_int {
with_slot(0, |slot| match &slot.current {
Some(Status::Live { has_camera, .. }) => *has_camera as c_int,
_ => 0,
})
}
/// 1 when the last polled `live` status had a real microphone feeding the
/// outbound track. 0 means listen-only: audio is still published, as silence.
#[no_mangle]
pub extern "C" fn joltmoq_status_has_mic() -> c_int {
with_slot(0, |slot| match &slot.current {
Some(Status::Live { has_mic, .. }) => *has_mic as c_int,
_ => 0,
})
}
// ── Video ───────────────────────────────────────────────────────────────────
/// Advance to the next feed carrying a frame the caller has not been given,
/// answering 1 while there was one.
///
/// Loop until it answers 0, reading [`joltmoq_frame_key`],
/// [`joltmoq_frame_width`], [`joltmoq_frame_height`] and
/// [`joltmoq_frame_rgba`] for each and handing those to whatever paints. Only
/// what changed comes over: a participant sitting still costs nothing, and a
/// decoder running ahead of the window is coalesced to its newest frame rather
/// than queued behind stale ones.
///
/// The key is the participant's nick, or `__local__` for the self-view.
#[no_mangle]
pub extern "C" fn joltmoq_frame_poll() -> c_int {
with_slot(0, |slot| {
slot.frame = None;
let Some(video) = slot.video.clone() else {
return 0;
};
let snapshot = video.snapshot();
for (key, frame) in &snapshot {
if slot.seen.get(key) == Some(&frame.gen) {
continue;
}
slot.seen.insert(key.clone(), frame.gen);
slot.frame = Some((key.clone(), frame.clone()));
return 1;
}
// Nothing new. Forget the keys nobody is publishing any more, so that
// if they come back the first frame of the new stream reads as new
// rather than as one already seen.
slot.seen
.retain(|k, _| snapshot.iter().any(|(live, _)| live == k));
0
})
}
/// Whose picture the last polled frame is: a nick, or `__local__`.
///
/// # Safety
/// The returned pointer is valid until the next call to this function.
#[no_mangle]
pub extern "C" fn joltmoq_frame_key() -> *const c_char {
let key = with_slot(String::new(), |slot| {
slot.frame
.as_ref()
.map_or(String::new(), |(k, _)| k.clone())
});
if key.is_empty() {
return empty_str();
}
FRAME_KEY.lend(key)
}
/// The last polled frame's width in pixels, or 0.
#[no_mangle]
pub extern "C" fn joltmoq_frame_width() -> c_int {
with_slot(0, |slot| {
slot.frame.as_ref().map_or(0, |(_, f)| f.width as c_int)
})
}
/// The last polled frame's height in pixels, or 0.
#[no_mangle]
pub extern "C" fn joltmoq_frame_height() -> c_int {
with_slot(0, |slot| {
slot.frame.as_ref().map_or(0, |(_, f)| f.height as c_int)
})
}
/// The last polled frame's pixels: `width * height * 4` bytes, row-major, 8
/// bits a channel, un-premultiplied and opaque. Null when there is no frame.
///
/// **Borrowed, and only until the next [`joltmoq_frame_poll`].** That is the
/// point of polling: a frame is a megabyte or two, and copying it into the
/// caller's memory so it can hand it straight to a texture upload would be two
/// copies a frame for nothing. Upload it, then poll again.
///
/// # Safety
/// Valid for reads of `width * height * 4` bytes until the next call to
/// [`joltmoq_frame_poll`] or [`joltmoq_stop`].
#[no_mangle]
pub extern "C" fn joltmoq_frame_rgba() -> *const u8 {
with_slot(std::ptr::null(), |slot| match &slot.frame {
Some((_, frame)) => frame.rgba.as_ptr(),
None => std::ptr::null(),
})
}
/// Everyone whose picture the call is currently carrying, one key a line.
///
/// A caller painting a tile per feed uses this to notice a tile it should stop
/// painting: someone who left stops appearing here, while their last frame
/// would otherwise hang on the wall for the rest of the call.
///
/// # Safety
/// The returned pointer is valid until the next call to this function.
#[no_mangle]
pub extern "C" fn joltmoq_video_keys() -> *const c_char {
let keys = with_slot(String::new(), |slot| match &slot.video {
Some(video) => {
let mut keys: Vec<String> = video.snapshot().into_iter().map(|(k, _)| k).collect();
keys.sort();
keys.join("\n")
}
None => String::new(),
});
if keys.is_empty() {
return empty_str();
}
VIDEO_KEYS.lend(keys)
}
// ── Devices ─────────────────────────────────────────────────────────────────
/// The cameras, one a line, each `id\tname\tdefault`.
///
/// Enumerating opens nothing, so this is safe to ask before a call and during
/// one. Empty on a machine with no camera, which is a normal answer.
///
/// # Safety
/// The returned pointer is valid until the next device-listing call.
#[no_mangle]
pub extern "C" fn joltmoq_cameras() -> *const c_char {
lend_devices(guard(Vec::new(), av_media::list_cameras))
}
/// The microphones, one a line, each `id\tname\tdefault`.
///
/// # Safety
/// The returned pointer is valid until the next device-listing call.
#[no_mangle]
pub extern "C" fn joltmoq_microphones() -> *const c_char {
lend_devices(guard(Vec::new(), av_media::list_microphones))
}
/// The speakers, one a line, each `id\tname\tdefault`.
///
/// # Safety
/// The returned pointer is valid until the next device-listing call.
#[no_mangle]
pub extern "C" fn joltmoq_speakers() -> *const c_char {
lend_devices(guard(Vec::new(), av_media::list_speakers))
}
fn lend_devices(list: Vec<av_media::MediaDevice>) -> *const c_char {
let rendered = devices(list);
if rendered.is_empty() {
return empty_str();
}
DEVICES.lend(rendered)
}
/// A device list as lines of `id\tname\tdefault`, where the last column is 1
/// for the system default and 0 otherwise.
///
/// Tab and newline are the delimiters because a device name may contain
/// anything else — "EMEET SmartCam C960, Mono" has spaces and a comma in it,
/// and a caller splitting on those gets nonsense. A name that somehow holds a
/// delimiter has it replaced rather than being allowed to forge a row.
///
/// The default is worth a column of its own: a picker that cannot mark it has
/// to guess, and "Default" is not reliably the first entry or a name anyone
/// can match on.
fn devices(list: Vec<av_media::MediaDevice>) -> String {
list.into_iter()
.map(|d| {
format!(
"{}\t{}\t{}",
d.id.replace(['\t', '\n'], " "),
d.name.replace(['\t', '\n'], " "),
d.is_default as u8
)
})
.collect::<Vec<_>>()
.join("\n")
}
// ── Dialling ────────────────────────────────────────────────────────────────
/// The SFU URL to hand [`joltmoq_start`], built from the IRC server the caller
/// is connected to and the JWT the server minted in `+freeq.at/av-token`.
///
/// `server` is whatever the client knows the server as — `irc.freeq.at:6697`,
/// `wss://irc.freeq.at/irc` — and both become `https://irc.freeq.at/av/moq`.
/// `jwt` and `instance` may be empty. The empty string comes back when the
/// server is not something a URL can be made of.
///
/// This lives here rather than in the caller because the rules are fiddly and
/// already tested on this side: which scheme maps to which, where the port
/// goes, and what to do with a path that was there.
///
/// # Safety
/// Every pointer is null or a NUL-terminated UTF-8 string; the returned pointer
/// is valid until the next call to this function.
#[no_mangle]
pub unsafe extern "C" fn joltmoq_sfu_url(
server: *const c_char,
jwt: *const c_char,
instance: *const c_char,
) -> *const c_char {
let server = borrowed(server);
let jwt = preference(borrowed(jwt));
let instance = preference(borrowed(instance));
let url = guard(String::new(), || {
av::sfu_moq_dial_url(&server, jwt.as_deref(), instance.as_deref())
.map(|u| u.to_string())
.unwrap_or_default()
});
if url.is_empty() {
return empty_str();
}
DIAL.lend(url)
}
/// 1 when dialling this server is worth attempting.
///
/// A remote SFU with no token accepts the connection and closes it, and
/// moq-lite then retries in a tight loop that looks, from the outside, exactly
/// like a hang. Asking first is cheaper than explaining that.
///
/// # Safety
/// Both pointers are null or NUL-terminated UTF-8 strings.
#[no_mangle]
pub unsafe extern "C" fn joltmoq_can_dial(server: *const c_char, jwt: *const c_char) -> c_int {
let server = borrowed(server);
let jwt = preference(borrowed(jwt));
guard(0, || av::can_dial_sfu(&server, jwt.as_deref()) as c_int)
}
/// A per-device call instance id — eight hex characters.
///
/// Two devices signed in as the same person need different ones, or their MoQ
/// broadcast paths collide and each unpublishes the other. The caller puts this
/// in its own `+freeq.at/av-instance` tag and hands the same one to
/// [`joltmoq_start`].
///
/// # Safety
/// The returned pointer is valid until the next call to this function.
#[no_mangle]
pub extern "C" fn joltmoq_new_instance() -> *const c_char {
DIAL.lend(guard("00000000".to_owned(), || {
format!("{:08x}", rand::random::<u32>())
}))
}
#[cfg(test)]
mod tests {
use super::*;
use std::ffi::{CStr, CString};
fn read(ptr: *const c_char) -> String {
unsafe { CStr::from_ptr(ptr) }.to_string_lossy().into_owned()
}
/// There is one session in this library, so there is one in its tests, and
/// cargo runs them in parallel. Anything touching the global slot takes
/// this first; without it a test asserting "nothing is live" fails because
/// another was mid-call at the time.
static ONE_AT_A_TIME: Mutex<()> = Mutex::new(());
fn exclusive() -> std::sync::MutexGuard<'static, ()> {
// A test that panicked while holding it poisoned it; that is the
// failure being reported, not a reason to fail every test after it.
ONE_AT_A_TIME.lock().unwrap_or_else(|e| e.into_inner())
}
#[test]
fn a_device_list_is_tab_and_newline_delimited() {
let list = vec![
av_media::MediaDevice {
id: "/dev/video0".to_owned(),
name: "EMEET SmartCam C960, Mono".to_owned(),
is_default: true,
},
av_media::MediaDevice {
id: "/dev/video2".to_owned(),
name: "Integrated".to_owned(),
is_default: false,
},
];
assert_eq!(
devices(list),
"/dev/video0\tEMEET SmartCam C960, Mono\t1\n/dev/video2\tIntegrated\t0"
);
}
#[test]
fn a_name_holding_a_delimiter_cannot_forge_a_row() {
let list = vec![av_media::MediaDevice {
id: "a\tb".to_owned(),
name: "two\nlines".to_owned(),
is_default: false,
}];
let rendered = devices(list);
assert_eq!(rendered, "a b\ttwo lines\t0");
assert_eq!(rendered.lines().count(), 1);
}
#[test]
fn the_sfu_url_is_built_from_whatever_the_server_is_known_as() {
let jwt = CString::new("tok.jwt.value").unwrap();
let inst = CString::new("abcd1234").unwrap();
for known_as in ["irc.freeq.at:6697", "wss://irc.freeq.at/irc"] {
let server = CString::new(known_as).unwrap();
let url =
read(unsafe { joltmoq_sfu_url(server.as_ptr(), jwt.as_ptr(), inst.as_ptr()) });
assert!(url.starts_with("https://irc.freeq.at/av/moq"), "{url}");
assert!(url.contains("inst=abcd1234"), "{url}");
}
}
#[test]
fn a_server_that_is_not_a_url_answers_the_empty_string() {
let server = CString::new(" ").unwrap();
let url = read(unsafe {
joltmoq_sfu_url(server.as_ptr(), std::ptr::null(), std::ptr::null())
});
assert_eq!(url, "");
}
#[test]
fn a_remote_sfu_without_a_token_is_not_worth_dialling() {
let remote = CString::new("wss://chat.example.com").unwrap();
let local = CString::new("ws://localhost:4443").unwrap();
let jwt = CString::new("tok").unwrap();
assert_eq!(
unsafe { joltmoq_can_dial(remote.as_ptr(), std::ptr::null()) },
0
);
assert_eq!(unsafe { joltmoq_can_dial(remote.as_ptr(), jwt.as_ptr()) }, 1);
assert_eq!(
unsafe { joltmoq_can_dial(local.as_ptr(), std::ptr::null()) },
1
);
}
#[test]
fn an_instance_id_is_eight_hex_characters_and_differs() {
let one = read(joltmoq_new_instance());
let two = read(joltmoq_new_instance());
assert_eq!(one.len(), 8);
assert!(one.chars().all(|c| c.is_ascii_hexdigit()), "{one}");
assert_ne!(one, two, "two devices would collide on the SFU");
}
#[test]
fn nothing_is_live_before_a_call_and_every_poll_answers_empty() {
let _guard = exclusive();
assert_eq!(joltmoq_is_live(), 0);
assert_eq!(joltmoq_poll_status(), JOLTMOQ_STATUS_NONE);
assert_eq!(read(joltmoq_status_text()), "");
assert_eq!(joltmoq_frame_poll(), 0);
assert!(joltmoq_frame_rgba().is_null());
assert_eq!(joltmoq_frame_width(), 0);
assert_eq!(read(joltmoq_frame_key()), "");
assert_eq!(read(joltmoq_video_keys()), "");
}
#[test]
fn a_control_with_no_call_under_it_is_inert() {
let _guard = exclusive();
// A UI that sends a mute as the call is ending must not take the
// process with it.
joltmoq_set_muted(1);
joltmoq_set_speaker_muted(1);
joltmoq_set_camera(1);
unsafe { joltmoq_set_mic_device(std::ptr::null()) };
joltmoq_stop();
assert_eq!(joltmoq_mic_level(), 0.0);
assert_eq!(joltmoq_is_live(), 0);
}
#[test]
fn stopping_does_not_hold_the_lock_a_status_callback_needs() {
let _guard = exclusive();
// The deadlock this guards: `stop` used to wait for the media task
// while holding the slot, and the task's status callback locks the
// slot to deliver an update — so neither could finish. Here a thread
// takes the slot the way that callback does, while the main thread
// stops. If stop waits under the lock, this never returns.
use std::sync::mpsc;
use std::time::Duration;
let (tx, rx) = mpsc::channel();
std::thread::spawn(move || {
for _ in 0..200 {
if let Ok(mut slot) = session_slot().lock() {
let generation = slot.generation;
slot.status.push((generation, Status::Ended));
slot.status.clear();
}
std::thread::sleep(Duration::from_millis(1));
}
let _ = tx.send(());
});
for _ in 0..50 {
joltmoq_stop();
}
assert_eq!(joltmoq_is_live(), 0);
rx.recv_timeout(Duration::from_secs(10))
.expect("the status thread never got the lock back");
}
#[test]
fn a_departed_session_cannot_end_the_one_that_replaced_it() {
let _guard = exclusive();
// Rejoining a call did exactly this. Teardown is spawned, so the old
// task finishes after the new call has started, and its "ended" landed
// in the same queue — where it read as the new call ending.
if let Ok(mut slot) = session_slot().lock() {
slot.generation = 7;
slot.status.clear();
// The old session (6) signing off, and the live one (7) saying it
// is up. Queued in that order, which is the order that hurt.
slot.status.push((6, Status::Ended));
slot.status.push((
7,
Status::Live {
has_camera: false,
has_mic: true,
},
));
}
// The stale "ended" is skipped, not acted on, and not left blocking
// the fresh one behind it.
assert_eq!(joltmoq_poll_status(), JOLTMOQ_STATUS_LIVE);
assert_eq!(joltmoq_status_has_mic(), 1);
assert_eq!(joltmoq_poll_status(), JOLTMOQ_STATUS_NONE);
if let Ok(mut slot) = session_slot().lock() {
slot.generation = 0;
slot.status.clear();
slot.current = None;
}
}
#[test]
fn stopping_makes_the_next_call_a_new_generation() {
let _guard = exclusive();
let before = session_slot().lock().map(|s| s.generation).unwrap_or(0);
joltmoq_stop();
let after = session_slot().lock().map(|s| s.generation).unwrap_or(0);
assert_ne!(before, after, "a stopped session must stop being current");
}
#[test]
fn a_frame_poll_yields_each_feed_once_until_it_changes() {
let _guard = exclusive();
let video = VideoFrameStore::new();
video.set("nandi", 1, 1, std::sync::Arc::from(vec![9u8; 4]));
if let Ok(mut slot) = session_slot().lock() {
slot.video = Some(video.clone());
slot.seen.clear();
}
assert_eq!(joltmoq_frame_poll(), 1);
assert_eq!(read(joltmoq_frame_key()), "nandi");
assert_eq!(joltmoq_frame_width(), 1);
// Same frame: nothing new to hand over.
assert_eq!(joltmoq_frame_poll(), 0);
// A new frame under the same key is new again.
video.set("nandi", 1, 1, std::sync::Arc::from(vec![3u8; 4]));
assert_eq!(joltmoq_frame_poll(), 1);
assert_eq!(read(joltmoq_frame_key()), "nandi");
assert_eq!(read(joltmoq_video_keys()), "nandi");
if let Ok(mut slot) = session_slot().lock() {
slot.video = None;
slot.seen.clear();
slot.frame = None;
}
}
}
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